let

rec {

  pkgs = import <nixpkgs> {};
  genAttrs' = pkgs.lib.genAttrs [ "x86_64-linux" "i686-linux" ];

in rec {

  build =
    { system ? "x86_64-linux" }:

  build = genAttrs' (system:

    let pkgs = import <nixpkgs> {inherit system;}; in

    with import <nixpkgs> { inherit system; };

    with pkgs;

    };

    });

  tests =
    { nixos ? ../nixos, system ? "x86_64-linux" }:
    let hydra = build { inherit system; }; in

  tests.install = genAttrs' (system:

    {
      install = simpleTest {
        machine =
          { config, pkgs, ... }:
          { services.postgresql.enable = true;
            services.postgresql.package = pkgs.postgresql92;
            environment.systemPackages = [ hydra ];
          };
        testScript =
          ''
            $machine->waitForJob("postgresql");

    let hydra = builtins.getAttr system build; in # build.${system}
    simpleTest {
      machine =
        { config, pkgs, ... }:
        { services.postgresql.enable = true;
          services.postgresql.package = pkgs.postgresql92;
          environment.systemPackages = [ hydra ];
        };

            # Initialise the database and the state.
            $machine->mustSucceed
                ( "createdb -O root hydra",
                , "psql hydra -f ${hydra}/libexec/hydra/sql/hydra-postgresql.sql"
                , "mkdir /var/lib/hydra"
                );

      testScript =
        ''
          $machine->waitForJob("postgresql");

            # Start the web interface.
            $machine->mustSucceed("HYDRA_DATA=/var/lib/hydra HYDRA_DBI='dbi:Pg:dbname=hydra;user=hydra;' hydra-server >&2 &");
            $machine->waitForOpenPort("3000");
          '';
      };
    };

          # Initialise the database and the state.
          $machine->mustSucceed
              ( "createdb -O root hydra",
              , "psql hydra -f ${hydra}/libexec/hydra/sql/hydra-postgresql.sql"
              , "mkdir /var/lib/hydra"
              );

          # Start the web interface.
          $machine->mustSucceed("HYDRA_DATA=/var/lib/hydra HYDRA_DBI='dbi:Pg:dbname=hydra;user=hydra;' hydra-server >&2 &");
          $machine->waitForOpenPort("3000");
        '';
    });